Axial fan

ABSTRACT

An axial fan includes a rotor, a rotor blade, a stator, and a housing. The housing includes a stator holder made of metal, a base made of metal and widened outwardly in a radial direction from a lower end portion of the stator holder, a rib extending outwardly in the radial direction from the base, and a housing cylinder connected to a radial-directional outer end portion of the rib. The housing cylinder extends in an axial direction and accommodates the rotor blade therein. A wind tunnel space in which air flows is provided between the base and the housing cylinder in the radial direction. A radial-directional outer side surface of the base is exposed in the wind tunnel space.

CROSS REFERENCE TO RELATED APPLICATION

The present invention claims priority under 35 U.S.C. § 119 to JapaneseApplication No. 2019-030529 filed on Feb. 22, 2019, the entire contentsof which are hereby incorporated herein by reference.

FIELD OF THE INVENTION

The present disclosure relates to an axial fan.

BACKGROUND

As a means for dissipating heat generated in a motor part in an axialfan, it can be considered that a motor housing is made of metal.However, the motor housing made of metal is more expensive and heavierthan a motor housing made of resin. In this regard, for example, it isknown an axial fan with a motor to which an impeller is mounted inside afan frame including a two-body structure of a resin frame and a metalframe. At a center of the resin frame, a motor base on which the motoris arranged is provided. In addition, the resin frame has a quadrangularshape or substantially quadrangular shape and has fitting parts providedat four corner regions and extending in an axial direction. The metalframe is quadrangular or substantially quadrangular shape, andthrough-holes are defined in four corner regions. By fitting the fittingparts of the resin frame into the through-holes of the metal frame, theresin frame and the metal frame are connected to each other.

In the axial fan, air flows in an axial direction in a wind tunnelformed between the motor and a part of the housing surrounding themotor. For this reason, heat radiation occurring at a part exposed tothe wind tunnel is effective.

However, when a part of the housing in which the motor is disposed ismade of resin, the heat conductivity toward the part exposed to the windtunnel is lower than when the above part is made of metal. Therefore,there is a concern that heat generated in the motor cannot besufficiently dissipated from the housing.

SUMMARY

An axial fan according to an example embodiment of the presentdisclosure may include a rotor that is rotatable about a central axisextending in a vertical direction, a rotor blade that is rotatabletogether with the rotor, a stator to drive the rotor, and a housing tosupport the stator. The housing may include a metallic stator holderextending in the axial direction, and supporting the stator, a metallicbase widened outwardly in the radial direction from a lower end portionof the stator holder, a rib extending outwardly in the radial directionfrom the base and facing the rotor blade in the axial direction, and ahousing cylinder including at least a portion made of resin andconnected to a radial-directional outer end portion of the rib. Thehousing cylinder may extend in the axial direction and accommodate therotor blade therein. A wind tunnel space in which air flows in the axialdirection by the rotor blade is provided between the base and thehousing cylinder in the radial direction. A radial-directional outerside surface of the base is exposed in the wind tunnel space.

The above and other elements, features, steps, characteristics andadvantages of the present disclosure will become more apparent from thefollowing detailed description of the example embodiments with referenceto the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an axial fan according to an exampleembodiment of the present disclosure.

FIG. 2 is a cross-sectional view showing a configuration example of theaxial fan according to an example embodiment of the present disclosure.

FIG. 3 is a partial cross-sectional view of a housing according to afirst example embodiment of the present disclosure.

FIG. 4 is a partial cross-sectional view of a housing according to asecond example embodiment of the present disclosure.

FIG. 5 is a partial cross-sectional view of a housing according to athird example embodiment of the present disclosure.

FIG. 6A is a perspective view of an axial fan according to a fourthexample embodiment of the present disclosure.

FIG. 6B is a partial cross-sectional view of a housing according to thefourth example embodiment of the present disclosure.

DETAILED DESCRIPTION

Hereinafter, example embodiments of the present disclosure are describedwith reference to the accompanying drawings.

In the present specification, in the axial fan 100, a direction parallelto a central axis CA is referred to as an “axial direction”. In theaxial direction, a direction from a base 420 of a housing 400 to a shaftholder 211, which will be described later, is referred to as an “upwarddirection”, and a direction from the shaft holder 211 to the base 420 isreferred to as a “downward direction”. In each component, an end part ofan upward side is referred to as an “upper end part”, and a position ofthe upper end part in the axial direction is referred to as an “upperend”. Further, an end part of a downward side is referred to as a “lowerend part”, and a position of the lower end part in the axial directionis referred to as a “lower end”. Further, in surfaces of components, anupward-facing surface is referred to as an “upper surface”, and adownward-facing surface is referred to as a “lower surface”.

A direction orthogonal to the central axis CA is referred to as a“radial direction”. In the radial direction, a direction approaching thecentral axis CA is referred to as “inwardly in the radial direction”,and a direction away from the central axis CA is referred to as“outwardly in the radial direction”. In each component, a radiallyinward end part is referred to as a “radial-directional inner end part”,and a position of the radial-directional inner end part is referred toas a “radial-directional inner end”. Furthermore, a radially outward endpart is referred to as a “radial-directional outer end part”, and aposition of the radial-directional outer end part is referred to as a“radial-directional outer end”. In addition, in side faces of eachcomponent, an inward-facing side face is referred to as a“radial-directional inner side face”, and an outward-facing side face isreferred to as a “radial-directional outer side face”.

A direction along a circumference about the central axis CA is referredto as a “circumferential direction”.

In addition, in this specification, the term “annular shape” includes anarch shape having a discontinuity on a part of an entire circumferenceabout the central axis CA, in addition to a shape that is continuouslyconnected without any discontinuity across an entire circumference inthe circumferential direction about the central axis CA.

In addition, it should be understood that the explanation describedabove is not strictly applied when the axial fan is assembled to actualequipment.

FIG. 1 is a perspective view of an axial fan 100 according to an exampleembodiment of the present disclosure. FIG. 2 is a cross-sectional viewillustrating a configuration example of the axial fan 100 according toan example embodiment of the present disclosure. FIG. 2 is across-sectional view taken along line A-A line of FIG. 1 and shows across-sectional structure of the axial fan 100 in the case where theaxial fan 100 is cut by an imaginary plane including a central axis CA.

The axial fan 100 is an air blower that causes air to flow in an axialdirection by rotation of a rotor blade 110. As shown in FIGS. 1 and 2,the axial fan 100 includes the rotor blade 110, an outer rotor typemotor 200, and a housing 400. The rotor blade 110, and a rotor 210(which will be described later) of the motor 200 are parts of a singlemember. The rotor blade 110 is rotatable together with the rotor 210about the central axis CA extending in a vertical direction. The motor200 drives and rotates the rotor blade 110. The housing 400 supports astator 220 (which will be described later) of the motor 200. Inaddition, a configuration of the housing 400 will be described later.

In addition, the axial fan 100 according to an example embodiment of thepresent disclosure is a fan motor, and the rotor blade 110 and a holder1 (which will be described later) of the rotor 210 are parts of a singlemember. However, the present disclosure is not limited to an example ofthe above example embodiment of the present disclosure, and the rotorblade 110 may be a member different from the holder 1. In this case, forexample, the axial fan 100 may further include an impeller having therotor blade 110 and an impeller base attached to the holder 1, with therotor blade being provided on the impeller base.

Next, a configuration of the motor 200 is described with reference toFIGS. 1 and 2. The motor 200 includes a shaft 201, the rotor 210, thestator 220, a substrate 240, a cover 250, and a resin filling part 260.

The shaft 201 is a rotation axis of the rotor blade 110 and the rotor210. The shaft 201 is rotatable together with the rotor blade 110 andthe rotor 210 about the central axis CA extending in the verticaldirection. The present disclosure is not limited to the above example,and the shaft 201 may be a fixed axis attached to the stator 220. Inaddition, when the shaft 201 is a fixed axis, a bearing for the rotor210 is provided between the shaft 201 and the rotor 210.

The rotor 210 is rotatable about the central axis CA extending in thevertical direction. The axial fan 100 is provided with the rotor 210.The rotor 210 has a shaft holder 211, the cylindrical holder 1 having alid, a rotor yoke 3, and a magnet 5.

The shaft holder 211 is attached to the shaft 201 at anaxial-directional upper part of the motor 200. In an example embodimentof the present disclosure, the shaft holder 211 is attached to anaxial-directional upper end part of the shaft 201 and is widenedoutwardly in the radial direction from a radial-directional outer sideface of the shaft 201.

The holder 1 holds the magnet 5. More specifically, the holder 1 holdsthe magnet 5 by interposing the rotor yoke 3. The holder 1 has a topplate 11 and a cylinder 12.

The top plate 11 has a plate shape which is widened in the radialdirection. More specifically, the top plate 11 has a circular disk shapeor substantially circular disk shape centered on the central axis CA andhaving an opening at a center thereof, and is widened from aradial-directional outer end part of the shaft holder 211 in the radialdirection.

The cylinder 12 extends downwardly from a radial-directional outer endpart of the top plate 11. The plurality of rotor blades 110 are providedon a radial-directional outer side face of the cylinder 12. The rotoryoke 3 is provided on a radial-directional inner side face of thecylinder 12.

The rotor yoke 3 is formed using a magnetic material. The rotor yoke 3has a cylindrical shape or substantially cylindrical shape extending inthe axial direction and holds the magnet 5. The rotor yoke 3 is providedon a radial-directional inner face of the holder 1. The magnet 5 isprovided on a provided on a radial-directional inner face of the rotoryoke 3.

The magnet 5 is disposed outwardly in the radial direction from thestator 220 and faces the stator 220 in the radial direction. The magnet5 has different magnetic poles, that is, N pole and S pole. The N poleand the S pole are alternately arranged in the circumferentialdirection. In an example embodiment of the present disclosure, themagnet 5 has an annular shape or substantially annular shape centered onthe central axis CA. However, the magnet 5 is not limited to the aboveexample and may include a plurality of segment magnets arranged in thecircumferential direction.

Next, the stator 220 drives the rotor 210. The axial fan 100 is providedwith the stator 220. More specifically, the stator 220 drives androtates the rotor 210 in the circumferential direction when the motor200 is driven. The stator 220 has an annular shape or substantiallyannular shape centered on the central axis CA.

The stator 220 includes a stator core 221, an insulator 222, and aplurality of coils 223. The stator core 221 is an annular orsubstantially annular magnetic body centered on the central axis CA,and, in an example embodiment of the present disclosure, the stator coreis a stacked body in which a plurality of plate-shaped electromagneticsteel plates are stacked. In an example embodiment of the presentdisclosure, a radial-directional inner end part of the stator core 221is fixed to a radial-directional outer side face of a stator holder 410(which will be described later) of the housing 400. A radial-directionalouter side face of the stator core 221 faces the magnet 5 in the radialdirection. The insulator 222 covers at least a part of the stator core221. The insulator 222 is an insulating member using a resin material orthe like. Each of the plurality of coils 223 is a winding member inwhich a conducting wire (reference numeral therefor is omitted) is woundaround the stator core 221 by interposing the insulator 222. An end partof the conducting wire is electrically connected to the substrate 240.

The substrate 240 is electrically connected to the conducting wire ofthe coils 223 and a connecting wire (not shown) drawn to the outside ofthe housing 400. In an example embodiment of the present disclosure, thesubstrate 240 is accommodated in the base 420.

The cover 250 has a cylindrical shape with a lid or substantiallycylindrical shape with a lid and accommodates the stator 220. The cover250 covers an opening (reference number thereof is omitted) formed in anupper end of the base 420. A lid (not shown) of the cover 250 has a diskshape or substantially disk shape centered on the central axis CA andhaving an opening formed in a center thereof, and is widened in theradial direction. The shaft 201 and the stator holder 410 are insertedinto and pass through the opening formed at the center of the lid. Acylinder (reference numeral thereof is omitted) of the cover 250 extendsdownwardly from a radial-directional outer end part of the lid. In anexample embodiment of the present disclosure, a lower end part of thecylinder is fitted into an upper end part of an outer cylinder 422.However, the present disclosure is not limited to the above example, andthe lower end part of the cylinder may be coupled to the upper end partof the outer cylinder 422 by, for example, snap fit, or the like.

In an example embodiment of the present disclosure, the resin fillingpart 260 fills the inside of the base 420 and the cover 250 with a resinmaterial. The resin filling part 260 covers at least a part of thestator 220. Furthermore, the resin filling part 260 also covers thesubstrate 240 and the like. In this way, it is possible to enhance thewaterproofness and dustproofness of the stator through the resin fillingpart 260. In addition, heat generated in the stator 220 is transferredto a metal part (which will be described later) of the housing 400 andthen dissipated. Therefore, overheating of the stator 220 caused by theresin filling part 260 may be suppressed.

Next, a configuration of the housing 400 is described with reference toFIGS. 1 and 2. A part of the housing 400 is made of resin. The remainingpart of the housing 400 is made of metal. The material of the metal partof the housing 400 is preferably a non-magnetic material. For example,an aluminum alloy such as ADC12, a magnesium alloy, zinc and alloythereof, austenitic stainless steel, or the like may be used as theabove-described material.

The housing 400 includes the stator holder 410, the base 420, a rib 430,a housing cylinder 440, and a flange 450.

The stator holder 410 is made of metal and has a cylindrical shape orsubstantially cylindrical shape extending in the axial direction. Thestator holder 410 supports the stator 220. The stator holder 410 isprovided with a bearing 411. The bearings 411 are arranged at upper andlower parts inside the stator holder 410. Further, the shaft 201 isinserted into the stator holder 410 and the bearings 411. The statorholder 410 rotatably supports the shaft 201 by interposing the bearing411. In an example embodiment of the present disclosure, the bearing 411is a ball bearing, but the present disclosure is not limited to theabove example and may be a sleeve bearing, or the like.

The base 420 is made of metal and widened outwardly in the radialdirection from a lower end part of the stator holder 410. The base 420has a cylindrical shape with a bottom or substantially cylindrical shapewith a bottom. The base 420 has a bottom lid 421 and the outer cylinder422. The bottom lid 421 has a disk shape or substantially disk shapecentered on the central axis CA and having an opening formed at a centerthereof, and is widened outwardly in the radial direction from the lowerend part of the stator holder 410. The outer cylinder 422 has acylindrical shape or substantially cylindrical shape that extendsupwardly from a radial-directional outer end part of the bottom lid 421.

The rib 430 connects the base 420 and the housing cylinder 440. In anexample embodiment of the present disclosure, the plurality of ribs 430are provided. The rib 430 extends outwardly in the radial direction fromthe base 420 and faces the rotor blade 110 in the axial direction. Aninner edge of the rib 430 in the radial direction is connected to aradial-directional outer side face of the base 420. Further, an outeredge of the rib 430 in the radial direction is connected to aradial-directional inner side face of the housing cylinder 440.

The rib 430 extends in the axial direction and is inclined in therotational direction of the rotor blade 110 as going downwardly. The rib430 functions as a stationary blade, and rectifies the flow of airdirected from an upper side to a lower side by a rotation of the rotorblade 110. Further, air flow strikes a positive pressure surface of therib 430 over a wide area. For that reason, even in the rib 430, it ispossible to dissipate the transferred heat. Such an effect isparticularly effective, for example when at least a part of the rib 430is made of metal.

At least a part of the housing cylinder 440 is made of resin. Thehousing cylinder 440 is connected to a radial-directional outer end partof the rib 430 and holds the base 420 by interposing the rib 430. Thehousing cylinder 440 extends in the axial direction and accommodates therotor blade 110. In addition, in an example embodiment of the presentdisclosure, the housing cylinder 440 accommodates the motor 200, thestator holder 410, the base 420, the rib 430, and the like therein. Awind tunnel (WT) extending in the axial direction is provided betweenthe cylinder 12 of the motor 200 and the housing cylinder 440 andbetween the outer cylinder 422 (which is described later) and thehousing cylinder 440 of the housing 400. When the axial fan 100 isdriven, air flows downwardly in the wind tunnel (WT) by rotation of therotor blade 110.

In the radial direction, a partial space of a wind tunnel (WT) in whichair flows in the axial direction by the rotor blade 110 is providedbetween the base 420 and the housing cylinder 440. Hereinafter, thepartial space is referred to as a wind tunnel space (WTs). In the windtunnel space (WTs), the radial-directional outer side face of the base420 is exposed.

As described above, since the stator holder 410 and the base 420 aremade of metal, heat generated in the stator 220 and the like isefficiently transferred to the base 420 via the stator holder 410. Theheat transferred to the base 420 is dissipated from theradial-directional outer side face of the base 420 facing the windtunnel space (WTs). Therefore, the heat dissipation of the housing 400can be improved.

Furthermore, a material of the stator holder 410 and a material of thebase 420 are preferably the same metal material. In this way, ascompared with the case where materials of both elements differ from eachother, a bonding strength force between both elements due to a change intemperature or an aging variation is not easily changeable and therebysuch bonding strength force is stable. Therefore, generation ofvibration and noise in the stator holder 410 and the base 420 can besuppressed. However, the present disclosure is not limited to theexample of the above example embodiment, and materials of both elementsmay differ from each other.

In an example embodiment of the present disclosure, the stator holder410 and the base 420 are parts of a single member. In this case, heattransferred from the stator 220 to the base 420 via the stator holder410 is better conducted, as compared with the case where the statorholder 410 and the base 420 are disparate members. Therefore, more heatmay be dissipated from the radial-directional outer side face of thebase 420 facing the wind tunnel space (WTs). Further, as compared with aconfiguration in which the stator holder 410 and the base 420 aredisparate bodies, rigidity of the housing 400 is higher. Therefore,generation of vibration and noise in the stator holder 410 and the base420 can be effectively suppressed. Furthermore, a process of assemblingthe stator holder 410 and the base 420 may be omitted.

However, the present disclosure is not limited to the example of theabove example embodiment, the stator holder 410 and the base 420 may bedisparate members. Even in this way, when materials of both elements arethe same, as compared with the case where materials of both elementsdiffer from each other, a bonding strength force between both elementsdue to a change in temperature or an aging variation is not easilychangeable and thereby such bonding strength force is stable. Therefore,it is possible to make it difficult for vibration and noise to begenerated. However, both elements may be disparate members made ofdifferent materials.

The flange 450 extends outwardly in the radial direction from a lowerend part of the housing cylinder 440 (see FIG. 1).

Next, a configuration of a metal part of the housing 400 is describedwith reference to the first to fourth example embodiments of the presentdisclosure.

FIG. 3 is a partial cross-sectional view of the housing 400 according tothe first example embodiment of the present disclosure. FIG. 3corresponds to a part B surrounded by a broken line in FIG. 2, and apartial cross-section of the housing 400 taken along line A-A in FIG. 1is viewed in the circumferential direction.

In the first example embodiment of the present disclosure, as shown inFIG. 3, the housing 400 further includes a first connector 401. Thefirst connector 401 is provided between an outer edge of the base 420 inthe radial direction and the inner edge of the rib 430 in the radialdirection. The first connector 401 connects the base 420 and the rib430. A first convexity 4011 and a first concavity 4012 are provided onthe first connector 401.

In FIG. 3, the base 420 has the first convexity 4011. The firstconvexity 4011 is provided on the outer edge of the base 420 in theradial direction, and more specifically, provided on aradial-directional outer side face of the outer cylinder 422. The firstconvexity 4011 protrudes from the outer edge of the base 420 in theradial direction to the inner edge of the rib 430 in the radialdirection. Also, in FIG. 3, the rib 430 has the first concavity 4012.The first concavity 4012 is provided on the inner edge of the rib 430 inthe radial direction, and is concave in a direction which is the same asa direction in which the first convexity 4011 protrudes. However, thepresent disclosure is not limited to the example in FIG. 3, the base 420may have the first concavity 4012 and the rib 430 may have the firstconvexity 4011.

In the first connector 401, that is, the first convexity 4011 may beprovided on one side of the outer edge of the base 420 in the radialdirection and the inner edge of the rib 430 in the radial direction. Inthis case, the first convexity 4011 protrudes from the one side towardthe other side. Moreover, the first concavity 4012 may be formed on theother side. In this case, the first concavity 4012 is concave in adirection which is the same as that in which the first convexity 4011protrudes.

In the first connector 401, the first convexity 4011 is accommodated inthe first concavity 4012 and is inserted into and held by the firstconcavity 4012 in the axial direction. In this way, for example, evenwhen the base 420 and the rib 430 are formed of different materials, thefirst concavity 4012 receives and holds the first convexity 4011 in theaxial direction such that both the base and the rib may be firmly fixed.Such a structure may be realized by, for example, an outsert moldingprocess, and the like. Here, in FIG. 3, by fitting the first convexity4011 into the first concavity 4012 in the radial direction, both thebase and the rib are connected. However, the present disclosure is notlimited to the example of FIG. 3, and the first convexity 4011 may befitted into the first concavity 4012 in the axial direction or thecircumferential direction so as to connect both elements.

In addition, in FIG. 3, the rib 430 is made of resin. Furthermore, thehousing cylinder 440 is also made of resin, and both the rib and thehousing cylinder are parts of a single member. That is, the outer edgeof the rib 430 in the radial direction is continuously connected to theradial-directional inner side face of the housing cylinder 440.

However, the present disclosure is not limited to this example, and atleast a part of the rib 430 may be made of metal. More specifically, atleast some rib 430 of the plurality of ribs 430 may be metallic. In thisway, heat generated in the stator 220 and the like is favorablytransferred to the metallic rib 430 via the stator holder 410 and thebase 420. Since air flowing in the axial direction through the windtunnel space (WTs) between the base 420 and the housing cylinder 440hits the metallic rib 430, so sufficient heat may be dissipated.Therefore, heat dissipation of the housing 400 may be further improved.

For the metallic rib 430, a metal material which is the same as that ofthe base 420 is preferably used. In this way, it is possible to reducemanufacturing cost. However, the present disclosure is not limited tothis example, and a metal material which differs from that of the base420 may be used for the metal rib 430.

FIG. 4 is a partial cross-sectional view of the housing 400 according tothe second example embodiment of the present disclosure. FIG. 4corresponds to a part B surrounded by a broken line in FIG. 2, and apartial cross-section of the housing 400 taken along line A-A in FIG. 1is viewed in the circumferential direction.

In the second example embodiment of the present disclosure, at least apart of the rib 430 is made of metal. More specifically, as shown inFIG. 4, a part of one rib 430 is made of metal. In this way, heatgenerated in the stator 220 and the like is favorably transferred to themetal part of the rib 430 via the stator holder 410 and the base 420.Since air flowing in the axial direction in the wind tunnel space (WTs)between the base 420 and the housing cylinder 440 hits this metal part,sufficient heat radiation may be performed. Accordingly, even in thiscase, the heat dissipation of the housing 400 may be further improved.

In the second example embodiment of the present disclosure, as shown inFIG. 4, the rib 430 includes a first rib piece 431 made of metal and asecond rib piece 432 made of resin.

The first rib piece 431 and the base 420 are parts of a single member.For that reason, an inner edge of the first rib piece 431 in the radialdirection is continuously connected to the outer edge of the base 420 inthe radial direction. However, the present disclosure is not limited tothe example of FIG. 4, and like as the first example embodiment, theinner edge of the first rib piece 431 in the radial direction may beconnected to the outer edge of the base 420 in the radial direction bythe first connector 401.

The second rib piece 432 and the housing cylinder 440 are parts of asingle member. Here, in FIG. 4, the housing cylinder 440 is made ofresin. For that reason, an outer edge of the second rib piece 432 in theradial direction is continuously connected to an inner edge of thehousing cylinder 440 in the radial direction. However, the presentdisclosure is not limited to the example of FIG. 4, or like as the thirdexample embodiment described later, the outer edge of the second ribpiece 432 in the radial direction may be connected to the inner edge ofthe housing cylinder 440 in the radial direction by a third connector403.

The housing 400 further includes a second connector 402. The secondconnector 402 is provided between an outer edge of the first rib piece431 in the radial direction and an inner edge of the second rib piece432 in the radial direction, and connects the first rib piece 431 andthe second rib piece 432. A second convexity 4021 and a second concavity4022 are provided on the second connector 402.

In FIG. 4, the first rib piece 431 has the second convexity 4021. Thesecond convexity 4021 is provided on the outer edge of the first ribpiece 431 in the radial direction, and protrudes from the outer edge ofthe first rib piece 431 in the radial direction toward the inner edge ofthe second rib piece 432 in the radial direction. In addition, in FIG.4, the second rib piece 432 includes the second concavity 4022. Thesecond concavity 4022 is provided at the inner edge of the second ribpiece 432 in the radial direction, and is concave in a direction whichis the same as a direction in which the second convexity 4021 protrudes.However, the present disclosure is not limited to the example of FIG. 4,and the first rib piece 431 may include the second concavity 4022 andthe second rib piece 432 may include the second convexity 4021.

That is, in the second connector 402, the second convexity 4021 may beprovided on one side of the outer edge of the first rib piece 431 in theradial direction and the inner edge of the second rib piece 432 in theradial direction. In this case, the second convexity 4021 protrudes fromthe one side toward the other side. Further, the second concavity 4022may be provided on the other side. In this case, the second concavity4022 is concave in a direction which is the same as a direction in whichthe second convexity 4021 protrudes.

In the second connector 402, the second convexity 4021 is accommodatedin the second concavity 4022 and is inserted into and held by the secondconcavity 4022 in the axial direction. In this way, for example, evenwhen the first rib piece 431 and the second rib piece 432 are formed ofdifferent materials, the second concavity 4022 receives and holds thesecond convexity 4021 in the axial direction such that both elements maybe firmly fixed. Such a structure may be realized by an outsert moldingprocess, and the like. Here, in FIG. 4, by fitting the second convexity4021 into the second concavity 4022 in the radial direction, bothelements are connected. However, the present disclosure is not limitedto the example of FIG. 4, and the second convexity 4021 may be fittedinto the second concavity 4022 in the axial direction or thecircumferential direction such that both elements may be connected.

FIG. 5 is a partial cross-sectional view of the housing 400 according tothe third example embodiment of the present disclosure. FIG. 5corresponds to a part C surrounded by a broken line in FIG. 2, and apartial cross-section of the housing 400 taken along line A-A in FIG. 1is viewed in the circumferential direction.

In the third example embodiment, at least a part of the rib 430 is madeof metal, and the housing cylinder 440 is made of resin. As shown inFIG. 5, the housing 400 further includes the third connector 403. Thethird connector 403 is provided between the outer edge of the rib 430 inthe radial direction and the inner edge of the housing cylinder 440 inthe radial direction. The third connector 403 connects the rib 430 andthe housing cylinder 440. A third convexity 4031 and a third concavity4032 are provided on the third connector 403.

In FIG. 5, the rib 430 has the third convexity 4031. The third convexity4031 is provided on the outer edge of the rib 430 in the radialdirection. The third convexity 4031 protrudes from the outer edge of therib 430 in the radial direction to the inner edge of the housingcylinder 440 in the radial direction. In addition, in FIG. 5, thehousing cylinder 440 includes the third concavity 4032. The thirdconcavity 4032 is provided on the inner edge of the housing cylinder 440in the radial direction, and is concave in a direction which is the sameas a direction in which the third convexity 4031 protrudes. However, thepresent disclosure is not limited to the example in FIG. 5, the rib 430may have the third concavity 4032 and the housing cylinder 440 may havethe third convexity 4031.

That is, in the third connector 403, the third convexity 4031 may beprovided on one side of the outer edge of the rib 430 in the radialdirection and the inner edge of the housing cylinder 440 in the radialdirection. In this case, the third convexity 4031 protrudes from the oneside toward the other side. Further, the third concavity 4032 may beprovided on the other side. In this case, the third concavity 4032 isconcave in a direction which is the same as a direction in which thethird convexity 4031 protrudes.

In the third connector 403, the third convexity 4031 is accommodated inthe third concavity 4032 and is inserted into and held by the thirdconcavity 4032 in the axial direction. In this way, for example, evenwhen the rib 430 and the housing cylinder 440 are formed of differentmaterials, the third concavity 4032 receives and holds the thirdconvexity 4031 in the axial direction both elements may be firmly fixed.Such a structure may be realized by an outsert molding process, and thelike. Here, in FIG. 5, by fitting the third convexity 4031 into thethird concavity 4032 in the radial direction, both elements areconnected. However, the present disclosure is not limited to the exampleof FIG. 5, and the third convexity 4031 may be fitted into the thirdconcavity 4032 in the axial direction or the circumferential directionso as to connect both elements.

Also, in the third example embodiment of the present disclosure, the rib430 and the base 420 may be parts of a single member. Further, amaterial of the rib 430 may be a metal material which is the same asthat of the base 420. That is, the inner edge of the rib 430 in theradial direction may be continuously connected to the outer edge of thebase 420 in the radial direction.

Alternatively, in the third example embodiment of the presentdisclosure, the first connector 401 similar to that in the first exampleembodiment may be provided between the outer edge of the base 420 in theradial direction and the inner edge of the rib 430 in the radialdirection. That is, the inner edge of the rib 430 in the radialdirection may be fixed to the outer edge of the base 420 in the radialdirection by inserting and holding the first convexity 4011 into and bythe first concavity 4012.

Alternatively, in the third example embodiment of the presentdisclosure, the rib 430 may include the first rib piece 431 and thesecond rib piece 432. At this time, the first rib piece 431 and the base420 are parts of a single member, and the second rib piece 432 isconnected to the housing cylinder 440 by the third connector 403.Further, the second connector 402 similar to that of the second exampleembodiment may be defined between the outer edge of the first rib piece431 in the radial direction and the inner edge of the second rib piece432 in the radial direction. That is, the outer edge of the first ribpiece 431 in the radial direction may be fixed to the inner edge of thesecond rib piece 432 in the radial direction by inserting and holdingthe second convexity 4021 into and by the second concavity 4022. In thiscase, the outer edge of the second rib piece 432 in the radial directionis connected to the inner edge of the housing cylinder 440 in the radialdirection by the third connector 403.

FIG. 6A is a perspective view of the axial fan 100 according to a fourthexample embodiment of the present disclosure, and FIG. 6B is a partialcross-sectional view of the housing 400 according to the fourth exampleembodiment of the present disclosure. FIG. 6B corresponds to a part Csurrounded by a broken line in FIG. 2, and a partial cross-section ofthe housing 400 taken along line D-D in FIG. 6A is viewed in thecircumferential direction.

In the fourth example embodiment of the present disclosure, at least apart of the rib 430 is made of metal. The housing cylinder 440 includesa first housing cylinder 441 which are made of metal and a secondhousing cylinder 442. The second housing cylinder 442 is attached to anupper end part of the first housing cylinder 441. The first housingcylinder 441 and the rib 430 or metal parts thereof are parts of asingle member. At least a part of the second housing cylinder 442 ismade of resin.

Having a part of the housing cylinder 440 to be made of metal makes itpossible to enhance rigidity of the housing cylinder 440. For thatreason, since thickness of the housing cylinder 440 may be thinner, theradial-directional size of the wind tunnel space (WTs) between the base420 and the housing cylinder 440 can be increased further and thereby toenlarge an air flowing area further.

Further, heat generated by the stator 220 and the like and transferredvia the stator holder 410, the base 420, and the rib 430 made of metalmay also be favorably dissipated from the first housing cylinder 441.Therefore, the heat dissipation of the housing 400 may be furtherenhanced.

The first housing cylinder 441 includes a first cylinder 4411 extendingin the axial direction and an inner wall 4412 having an annular shape orsubstantially annular shape. The inner wall 4412 protrudes upwardly froman upper face of the first cylinder 4411 and extends in thecircumferential direction. In FIG. 6B, the inner wall 4412 protrudesfrom a radial-directional inner end part of the upper face of the firstcylinder 4411.

The second housing cylinder 442 includes a second cylinder 4421extending in the axial direction, and outer wall 4422 having an annularshape or substantially annular shape. The outer wall 4422 protrudesdownwardly from a lower face of the second cylinder 4421 and extends inthe circumferential direction. In FIG. 6B, the outer wall 4422 protrudesfrom a radial-directional outer end part of the lower face of the secondcylinder 4421, and is disposed on a radial-directional outer side of theinner wall 4412.

A radial-directional outer side face of the inner wall 4412 is incontact with a radial-directional inner side face of the outer wall4422. In this way, it is possible to more firmly connect the firsthousing cylinder 441 and the second housing cylinder 442. For example,when the first housing cylinder 441 made of metal and the second housingcylinder 442 made of resin are outsert-molded, the outer wall 4422 ofthe second housing cylinder 442 presses the inner wall 4412 of the firsthousing cylinder 441 toward the radial-directional inner side by heatshrinkage of the resin such that both the first and second housingcylinders may be firmly connected. Alternatively, the inner wall 4412may be fitted into the inner side of the outer wall 4422. Alternatively,the inner wall 4412 may be inserted into and pass through the outer wall4422, and may be bonded to the outer wall 4422 by using an adhesive orthe like.

Further, as described above, the housing 400 includes the flange 450. Inthe fourth example embodiment of the present disclosure, the flange 450extends outwardly in the radial direction from a lower end part of thefirst housing cylinder 441. The flange 450 is preferably made of metal,and more preferably made of metal which is the same as that of the firsthousing cylinder 441. In addition, more preferably, the flange 450 andthe first housing cylinder 441 are parts of a single member. Having theflange 450 used for attachment of the axial fan 100 to be made of metalmay further enhance heat dissipation of the housing 400. Furthermore,having the flange 450 and the first housing cylinder 441 to be parts ofa single member may further improve heat dissipation of the housing 400.In addition, since the axial fan 100 may be firmly and securelyattached, generation of vibration and noise may be more effectivelysuppressed.

The present disclosure is useful for an air blowing apparatus in which apart of the housing is exposed in a space through which air flows.

While example embodiments of the present disclosure have been describedabove, it is to be understood that variations and modifications will beapparent to those skilled in the art without departing from the scopeand spirit of the present disclosure. The scope of the presentdisclosure, therefore, is to be determined solely by the followingclaims.

What is claimed is:
 1. An axial fan comprising: a rotor that is rotatable about a central axis extending in a vertical direction; a rotor blade that is rotatable together with the rotor; a stator to drive the rotor; and a housing to support the stator; wherein the housing includes: a stator holder made of metal and extending in an axial direction, and supporting the stator; a base made of metal and widened outwardly in a radial direction from a lower end portion of the stator holder; a rib extending outwardly in the radial direction from the base and facing the rotor blade in the axial direction; and a housing cylinder including at least a portion made of resin, and connected to a radial-directional outer end portion of the rib; the housing cylinder extends in the axial direction and accommodates the rotor blade therein; a wind tunnel space in which air flows in the axial direction by the rotor blade is provided between the base and the housing cylinder in the radial direction; a radial-directional outer side surface of the base is exposed in the wind tunnel space; the rib includes a first rib piece made of metal and a second rib piece made of resin; the first rib piece and the base are defined a single unitary structure; the second rib piece and the housing cylinder are defined by a single unitary structure; a second connector connecting the first rib piece and the second rib piece is provided between an outer edge of the first rib piece in the radial direction and an inner edge of the second rib piece in the radial direction; in the second connector, a second convexity is provided on one e of the outer edge of the first rib piece in the radial direction and the inner edge of the second rib piece in the radial direction, the second convexity protrudes from the on side toward another side; a second concavity, which is concave in a direction that is the same as a direction in which the second convexity protrudes, is provided on the another side; and the second convexity is accommodated in the second concavity, and is inserted into and held by the second concavity hi the axial direction.
 2. The axial fan of claim 1, wherein the stator holder and the base are defined by a single unitary structure.
 3. The axial fan of claim 1, wherein a first connector connecting the base and the rib is provided between an outer edge of the base in the radial direction and an inner edge of the rib in the radial direction; in the first connector, a first convexity is provided on one side of the outer edge of the base in the radial direction and the inner edge of the rib in the radial direction, the first convexity protrudes from the one side toward the another side; a first concavity, which is concave in a direction that is the same as a direction in which the first convexity protrudes is provided on the another side; and the first convexity is accommodated in the first concavity, and is inserted into and held by the first concavity in the axial direction.
 4. The axial fan of claim 1, wherein a third connector connecting the rib and the housing cylinder is provided between an outer edge of the rib in the radial direction and an inner edge of the housing cylinder in the radial direction; in the third connector, a third convexity is provided on one side of the outer edge of the rib in the radial direction and the inner edge of the housing cylinder in the radial direction, the third convexity protrudes from the one side toward the another side; a third concavity, which is concave in a direction that is the same as a direction in which the third convexity protrudes, is provided on the another side; and the third convexity is accommodated in the third concavity, and is inserted into and held by the third concavity in the axial direction.
 5. The axial fan of claim 1, wherein the housing cylinder includes: a first housing cylinder made of metal; and a second housing cylinder attached to an upper end portion of the first housing cylinder; the first housing cylinder and the rib are defined by a single unitary structure.
 6. The axial fan of claim 5, wherein the first housing cylinder includes: a first cylinder extending in the axial direction; and an inner wall with an annular or substantially annular shape and protruding upwardly from an upper surface of the first cylinder and extending in a circumferential direction; the second housing cylinder includes: a second cylinder extending in the axial direction; and an outer wall with an annular or substantially annular shape and protruding downwardly from a lower surface of the second cylinder and extending in the circumferential direction; and a radial-directional outer side surface of the inner wall is in contact with a radial-directional inner side surface of the outer wall.
 7. The axial fan of claim 5, wherein the housing includes a flange made of metal and extending outwardly in the radial direction from a lower end portion of the first housing cylinder.
 8. The axial fan of claim 1, wherein the rib extends in the axial direction and is inclined in a rotational direction of the rotor blade as extending downwardly.
 9. The axial fan of claim 1, further comprising a resin covering at least a portion of the stator. 